Polyoxyethylene-base nonionic compounds have been known for long to be useful as surfactant and detergent, and the physical properties and synthesis methods of them and the emulsifying, solubilizing and cleansing characteristics thereof have been studied and reported in fair detail (see Martin J. Schick, NONIONIC SURFACTANTS PHYSICAL CHEMISTRY (1987) and so on).
Such polyoxyethylene-base nonionic surfactants have high detergency and can also be used favorably in a state combined with other ionic surfactant, so that various combinations thereof with other surfactants have been proposed.
With respect to household and industrial detergents, meanwhile, a formulation having a higher surfactant concentration has recently been required from the standpoints of energy saving in the production or transportation, resource nursing, and diminution in the containers to be disposed of. However, new problems occur with an increase in the surfactant concentration of the detergent. Specifically, a surfactant composition containing a surfactant in a higher concentration fails in removing stains completely owing to its poor penetrating power, when the composition is applied or sprayed directly on stains or the object to be cleansed is immersed in the composition, followed by washing or rinsing in large amount of water.
U.S. Pat. No. 4,134,854 discloses a specific polyalkylene oxide adduct as a low-melting nonionic surfactant. However, this US Patent Specification is silent on the favorable concentration of the surfactant composition containing this adduct or on the penetrating power of the high-concentration surfactant composition containing the adduct.
U.S. Pat. No. 3,567,784 discloses that another specific polyalkylene oxide adduct has a high cloud point and a low gelation temperature. However, this US Patent Specification is silent on the high-concentration surfactant composition containing this adduct.
Furthermore, JP-A 47-9561 (corresponding to U.S. Pat. No. 4,115,457) discloses a process for the preparation of another specific polyalkylene oxide adduct which is useful as a scouring agent or dyeing aid. However, it is silent on high-concentration surfactant compositions exhibiting high penetrating power.
Further, JAOCS, Vol. 63, No. 9, pp. 1201-1208 (1986) discloses the physical properties of similar polyalkylene oxide adducts.